<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 200px;
            height: 200px;
            background: red;
        }
        .box2{
            width: 100px;
            height: 100px;
            background: blue;
        }
    </style>
</head>
<body>
    <div class="box1">
        <div class="box2">

        </div>
    </div>
</body>
</html>
<script>
    var box2Ele = document.querySelector(".box2");
    box2Ele.onclick = function(e){
        var target = e.target || e.scrElement;
        console.log(target)
    }
</script>